Davidb,
See if this helps I got the information from Daytona sport bikers forums.
The power output of an internal combustion engine is significantly influenced by barometric pressure, ambient air temperature, and air humidity.
The lower ambient barometric pressure reduces the density of the air, thus reduces the amount of oxygen filling the cylinder for each cycle, resulting in lower power output. Conversely, higher barometric pressure increases power.
The lower ambient air temperature results in increased density of the air, thus increases the amount of oxygen filling the cylinder for each cycle, resulting in higher power output. Conversely, higher air temperature reduces power output.
Lower air humidity (= less water vapor) leaves more room for oxygen per cubic foot of air, thus increases the amount of oxygen filling the cylinder for each cycle, resulting in higher power output. Conversely, higher air humidity reduces power output.
Several Standards organizations have determined methods for estimating engine power under reference conditions. The best known organizations are:
ISO (International Standards Organization), worldwide
SAE (Society of Automotive Engineers), USA
ECE (European Community), Europe
JIS (Japanese Institute for Standardization), Japan
DIN (Deutsche Industrie Norm), Germany
There are power correction standards for gasoline and Diesel engines, for applications in road vehicles, stationary engines, or marine engines, etc. For a motorcycle dynamometer, relevant standards are those generally intended for gasoline engines in road vehicles and those specific to motorcycles.
SAE -- The SAE standard applied is a modified version of the SAE J1349 standard of June 1990. Power is corrected to reference conditions of 29.23 InHg (99 kPa) of dry air and 77 F (25
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Topic: Dyno Numbers? (Read 240637 times)